Yes, it comes back in most classic tea books.
Especially Lu Yu The classic of tea (Cha Ching) (~ 800) (translation FR Carpenter):

When the water is boiling, it must look like fishes’ eyes and give off but the hint of a sound. When at the edges it chatters like a bubbling spring and looks like pearls innumerable strung together, it reaches the second stage. When it leaps like breakers majestic and resounds like a swelling wave, it is at its peak. Any more and the water will be boiled out and should not be used.

In short it is a way to determine the temperature of the water (and thereby its readiness) by eye and ear.

I have heard of this and apparently, James Norwood Pratt wrote about it in his book The New Tea Lovers Treasury.

It’s described briefly on Wikipedia and appears to come from the Chinese cooking culture, Levels of boiling

There are five levels and they compare to the different relative temperatures needed to brew different types of tea. They are (listed coolest to hottest) shrimp eyes, crab eyes, fish eyes, rope of pearls, and raging torrent.

@bram and @peter that was interesting research. It should answer @lahikmajoe‘s questions. I’d say he’s perhaps looking for shrimp eyes. I myself prefer the raging torrent.

An easily accessible description of the different ways to judge water temperature (without a thermometer) is the one in Master Lam Kam Chuen’s very good book The Way of Tea.
Judging water temperature by sight is called Hsing Pien (“orm distinguising”). Master Chuen calls the “raging torrent” level Old Man Water which should not be used for making tea (but is the most common form of water used in Western Cultures for making tea). Neither should one use crab-eye water for preparing tea.

The other ways of judging water temperature are “sound distinguishing”, or Sheng Pien. I find that probably the easiest method for most people, since you can’t see the water in most electric kettles. If you experiment for some time by keeping a thermometer in the kettle, you’ll get pretty good at judging the sound of your kettle in regards to temperature.

The last way of judging water temperature is “air distinguishing” or Chi Pien. This is the hardest to master I find and involves judging the form of steam rising from your kettle. But maybe it’s just me who finds this hard.

I also want to add that these descriptions are used because these were familiar to people in traditional society. Most Chinese cooking styles for fish and shrimp don’t remove the head. So the sizes of their eyes are always obvious to people. Heads are usually my favorite parts of fish, shrimp and lobster 😀

Oh well, I guess everything can remind me of food 😉

@dinahsaur:
I agree a very nice book.

I’m used to the term Fish Eyes associated with the water temp for green tea. Not sure when it became a part of my vocabulary, but my children even use the term when making tea 🙂

Just remembered this blogpost by Marcus Stout

http://ruminations.goldenmoontea.com/the-5-different-stages-of-boiling-water-and-h

Well @lahikmajoe if all these replies don’t answer your forum post then I don’t know what will.
Thanks everybody for your input. Every single reply made for good reading. I spent some time looking at all the referenced texts. A number of those I’m aware of. Fascinating. Thanks for the blog link too @manx .
I can go by sight when I boil my water in the glass Breville, but I also go by sound. In the Breville it’s a mechanical peep, in most kettles it’s the flick of the kettle switch. Yes, I know very funny indeed.
I do actually go by sounds like @yaya mentioned. I’m so used to knowing what boiling water sounds like in a stove pot I do recognize it now. And actually probably the look of the steam too. I do a lot of cooking…
J.